NASA’s Perseverance mission has been collecting samples for later retrieval and return to Earth. Now, it’s unclear how we’ll get those samples home.

Perseverance selfie at Skinner Ridge
NASA’s Perseverance rover puts its robotic arm to work around a rocky outcrop called “Skinner Ridge” in Mars’s Jezero Crater. Composed of multiple images, this mosaic shows layered sedimentary rocks in the face of a cliff in the delta, as well as one of the locations where the rover abraded a circular patch to analyze a rock’s composition.
NASA / JPL-Caltech / ASU / MSSS

For the past three years, NASA's Perseverance rover has been exploring Jezero Crater on Mars in unprecedented fashion. For the first time in history, a robotic emissary has been collecting rock and atmospheric samples from another planet that are destined for analysis back on Earth, where scientists will be able to employ techniques that simply aren't available in situ.

The question is, how will we get the samples from there to here?

NASA and the European Space Agency (ESA) have been pursuing a plan to return the samples since before Perseverance launched, named (for now) the Mars Sample Return mission. And the plan was...complicated. First, NASA would launch a Sample Retrieval Lander in 2028. Once it landed on Mars, Perseverance would deliver samples to the lander. (Helicopters or rovers might accompany the lander to aid in retrieval.) The lander would then launch off of Mars via a Mars Ascent Vehicle. The MAV would go to orbit around the Red Planet, where it would meet another vehicle that would then carry the mission back to Earth. (Find a full, illustrated outline of the mission concept here.)

Mars Sample Return
A sample return tube sits on the surface of Mars, awaiting collection.

When Perseverance launched, the samples were expected to be returned by 2031 at earliest. The astronomy community's decadal survey affirmed the mission at a budget of $5-7 billion. The Mars Sample Return passed its first independent review board evaluation, albeit with extensive recommendations for improvement. However, a second independent review didn't go so well, finding that the mission couldn't be accomplished within the current budget. Either the mission would need to be stretched out to a return date of 2040, or the budget needed to grow significantly, to $8-11 billion.

Today, NASA Administrator Bill Nelson acknowledged the second independent review's report, calling the needed budget "too expensive" and the 2040 timeline "unacceptably too long." The needed funding for Mars Sample Return, as it is now, would cannibalize other, existing missions, he said, including the Dragonfly mission to Saturn's moon Titan, the DAVINCI and VERITAS missions to Venus, and the Near-Earth Object Surveyor.

Instead, Nelson and Associate Administrator Nicky Fox are calling for alternative mission architectures. "I have asked our folks to reach out with a request for information to industry, to the Jet Propulsion Laboratory, and to all NASA centers," Nelson said at the April 15th press conference, "and to report back this fall an alternate plan that would get [the samples] back quicker and cheaper."

What those alternatives would look like is, at this point, anyone's guess. Fox did, however, emphasize that the agency is looking for tried-and-true technologies. "Thereby, we can lower the risk and the cost and also the time for development," she added. "Anything requiring huge leaps in technology usually, from experience, takes a lot of time."

"The solicitation should go out tomorrow," Fox added, outlining a two-step process. "The due date for proposals would be May 17th. . . . Once we've got the award to the various partners, we would give them 90 days to respond with their studies." After the studies are received, NASA will need to evaluate them; Fox did not give an estimated time frame for any decisions.

"Remember, we were put in this situation because of the cutbacks by Congress . . . that's what we are having to respond to," Nelson said. "We made the choice that, of those that were arguing that this program should be zeroed out, that this was too important to our country, that returning the samples from Mars remains an important operation."


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Andrew James

April 16, 2024 at 5:30 pm

I had a visitor with her ten-year-old son. He saw the picture of the sample return tube that sits on the surface of Mars. He immediately said it look like a Jedi light sabre. I laughed, because I thought it was true. But I had another thought. Perhaps instead we should be promoting the retrieval mission to kids, and use that as motivation in bringing it back to Earth. Crazy, but it might help? NASA? 🙂

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Anthony Barreiro

April 16, 2024 at 8:00 pm

$5 billion to $7 billion dollars is a lot of money. But let's put it in context. A 2021 audit by the NASA Office of the Inspector General concluded that by 2025 NASA will spend $93 billion on the Artemis mission to put astronauts on the Moon. Humans walked on the Moon 50 years ago. Let's spend some of the Artemis money bringing a few pieces of Mars to Earth.

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April 19, 2024 at 7:26 pm

This project always seemed to me to be a half baked add-on to the main mission. It might be just as efficient to abandon this retrieval in favor of an admittedly narrower direct land and retrieve mission using one of the more robust launch vehicles we now have or are developing. The current samples will still be there for future expeditions to retrieve (if still believed to have value).

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April 20, 2024 at 3:00 am

I have a great idea: Let's re-implement a tax structure like the one we had in 1945-1964: You know, the period that was the longest peacetime boom in American history? The super-rich and the corporations would finally pay their fair share, and we wouldn't have to treat our space programs like stepchildren!

Oh, but you have to know History for that...sorry, wrong venue. And dear old Elmo and Chrome-dome wouldn't have their rockets to play with...

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April 20, 2024 at 12:31 pm

While I think the money would be well spent, I note that the estimated cost was raised from $5-7 billion to $8-11 billion (and it would likely be a miracle if that were the last raise of the estimate). Given that, blaming the problem on "cutbacks by Congress" doesn't seem to pass the smell test.

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Mike McCabe

April 24, 2024 at 11:18 am

Get Musk involved. He's purportedly interested in Mars, and he has the money. Call him in to help finish the mission.

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